Novel n-(piperazinylethyl)-carbamates

ABSTRACT

N-(piperazinylethyl)-carbamates are prepared in good yield by reacting at an elevated temperature an N-hydrocarbylcarbamate with triethylenediamine or an N-hydrocarbylcarbamate, triethylenediamine and an added alkylating agent. The Npiperazinyl derivatives so-formed are useful as catalysts in the manufacture of polyurethanes, in the preparation of acid-soluble and acid-dyeable polyurethanes.

United States Patent H 1 1 3,719,680

Abbate et al. 1 March 6, 1973 NOVEL N -(PIPERAZINYLETHYL)- [56]References Cited ARBAMATES C UNITED STATES PATENTS [75] Inventors:Franklin W. Abbate, North Haven;

William J Farrissey, Jr" Northford, 3,138,597 6/1964 SChut ..260/268 PAboth of Conn. Primary Examiner-Donald G. Daus Asslgneei l PJ p yKalamazoo, AttorneySteward & Steward, Merrill F. Steward, Mlch- DonaldT. Steward, Walter D. Hunter and John 22 Filed: March 2,1970

[21] Appl.No.: 15,925 [57] ABSTRACT N-(piperazinylethyl)-carbamates areprepared in good 260/268 260/268 P yield by reacting at an elevatedtemperature an N- 260/463 260/ 7 260/ /579, hydrocarbylcarbamate withtriethylenediamine or an 260/655 R, 260/864 N-hydrocarbylcarbamate,triethylenediamine and an [51] Int. Cl. ..C07d 51/70 added alkylatingagent. The N-piperazinyl derivatives Field of Search 6 243 AA so-formedare useful as catalysts in the manufacture of polyurethanes, in thepreparation of acid-soluble and acid-dyeable polyurethanes.

4 Claims, No Drawings NOVEL N-(PIPERAZINYLETHYL)-CARBAMATES BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention relates tonovel N-(piperazinylethyl)- carbamates and to a method for theirpreparation and relates particularly to N-(piperazinylethyl)-carbamatessynthesized by reacting at an elevated temperature anN-hydrocarbylcarbamate with triethylenediamine or anN-hydrocarbylcarbamate, triethylenediamine and an added alkylatingagent.

2. Description of the Prior Art The only work previously described inthe art in which triethylenediamine has been employed as a reactant togive a piperazine derivative is that of Ross et al, JACS 85, 3999 (1963)who reacted 2,4- dinitrochlorobenzene with triethylenediamine to formthe compound:

SUMMARY OF THE INVENTION The present invention comprises novel compoundsof the formula:

wherein R is hydrocarbyl of one to 12 carbon atoms, wherein R and R areselected from the group consisting of CH straight chain lower alkyl; CHCI I R wherein R is selected from the group consisting of CH O, straightchain lower alkoxy and aryloxy of not more than 12 carbon atoms and withthe proviso that when R is CII CH R then R is the same substituentgroup, and to a process for preparing such novel compounds.

The novel piperazine derivatives of this invention can be utilized ascatalysts in preparing valuable polyurethane products, in thepreparation of acid-dyeable modified polyesters and for the modificationof polyurethanes prepared from a polyester polyol and a polyisocyanateto yield acid-dyeable or acid-soluble polymers.

Throughout this specification the term hydrocarbyl of from one to 12carbon atoms" means the monovalent radical resulting when one hydrogenatom is removed from the parent hydrocarbon having the requisite numberof carbon atoms. Illustrative of such groups are (a) alkyl, such asmethyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,decyl, undecyl, dodecyl; (b) alkenyl, such as vinyl, allyl, butenyl,pentenyl, hexenyl, octenyl, dodecenyl, etc.; (0) aralkyl, such asbenzyl, phenylethyl, phenylpropyl, phenylhexyl, naphthylmethyl, etc.;(d) aryl, such as phenyl, tolyl, xylyl, naphthyl, bis-phenylyl, etc.;(e) alkaryl, such as ethylphenyl, isopropylphenyl, ethylxylyl,methylnaphthyl, etc.; (f) cycloalkyl, such as cyclobutyl, cyclohexyl,cyclooctyl, cyclodecyl, etc.; and (g) cycloalkenyl such as cyclobutenyl,cyclopentenyl,

cyclohexenyl, cyclooctenyl, cyclododecenyl, etc., and isomeric forms ofmembers of the above groups. The phrase straight chain lower alkyl inthis specification means alkyl of from two to eight inclusive carbonatoms, as exemplified by ethyl, propyl, butyl, pentyl, hexyl, heptyl,octyl, and isomeric forms thereof. The phrase straight chain loweralkoxy as used herein means straight chain alkoxy of from two to eightinclusive carbon atoms including ethoxy, propoxy, butoxy pentyloxy,hexyloxy, heptyloxy and octyloxy. The term aryloxy of not more than 12carbon atoms" means aryloxy such as phenoxy, xyloxy, naphthoxy,ethylphenoxy, n-propylxyloxy, isobutylphenonoxy, etc. A wide variety ofcatalysts are employed in the preparation of polyurethanes andespecially in preparing polyurethane foams by the reaction ofpolyisocyanates with polyols in the presence of a fluorocarbon foamingagent. One of the most important of these catalysts istriethylenediamine which is employed in substantial quantities in theurethane industry in foam preparation as well as in the manufacture ofother urethane products. It has been found that the novel N-(piperazinylethyl)-carbamates of this invention are valuable urethanecatalysts which may be employed as a substitute for a part or all of thetriethylenediamine commonly utilized in the production of polyurethanesby interaction of diisocyanates and polyols or in the production ofpolyureas by interaction of diisocyanates and polyamines. Methods forproducing such polyurethanes and polyureas in the form of film, fibersand foams utilizing the conventionally employed diisocyanates andpolyols together with the novel catalysts of this invention will bereadily apparent to those skilled in the art. Conventional proceduresfor the synthesis of such polyurethanes are described by Saunders etal., Polyurethanes, Chemistry and Technology, Part II, IntersciencePublishers, 1964, pp. 299-451.

Examples of art-recognized polyols which an be employed alone, or asmixtures, in preparing polyurethanes includes the following:

I. Aliphatic diols, such as ethylene glycol, 1,2-

propylene glycol, 1,4-butanediol, 1,2-hexanediol, l,5-pentanediol,1,2-hexanediol, etc.;

2. aliphatic triols, such as trimethylolmethane,

trimethylolcthane, 1,2,3-hexanetriol, 1,1,1- trimethylolhexane, etc.; 3.aliphatic tetrols, such as erythritol, pentaearythritol, etc.;

4. aliphatic pentols, such as arabitol, xylitol, etc.;

5. aliphatic hexols, such as mannitol, sorbitol, dipentaerythritol, etc;

6. aniline-alkylene oxide diol adducts; and adducts prepared by reactingany of the above-named compounds (1) through (5) above with one or moremolar proportions of ethylene oxide, propylene oxide, 1,2-butyleneoxide, or mixtures thereof.

Any of the prior art polyisocyanates can be used as reactants inpreparing polyurethane products when utilizing the novel products ofthis invention as catalysts e.g., diisocyanate, -tolylene diisocyanate,2,6- tolylene diisocyanate, 4,4-diphenylmethane diisocyanate,dianisidine diisocyanate, tolidine diisocyanate, hexamethylenediisocyanate, m-xylyene diisocyanate, 1,5naphthalene diisocyanate, andother diand higher polyisocyanates such as those listed in the table ofSiefken, Ann. 562, 122-135 (1949). Preferred polyisocyanates, however,are products obtained by phosgenation of mixtures of methylene-bridgedpolyphenyl polyamines obtained by the interaction of formaldehyde,hydrochloric acid, and primary aromatic amines, for example, aniline,o-chloroaniline, otoluidine, or mixtures thereof. Such polyisocyanatesare known in the art, e.g., US. Pat. Nos. 2,683,730; 2,950,263; and3,012,008; Canadian Pat. No. 665,495; and German specification No.1,131,877.

In preparing polyurethane products employing the novelN-(piperazinylethyl)-carbamates of this invention as catalysts, or as apart of the catlyst mixture, by reaction of any of the polyisocyanatesconventionally employed in the art with the available polyols, blowingagents, surfactants, cell-openers and the like adjuvants commonlyemployed for the production of polyurethane products may be used. Ifdesired, special polyols such as the phosphorus-containing polyols canbe incorporated in the polyurethane reaction mixture in order to impartfire retardent properties to the resulting foam. Examples of suchphosphorus-containing polyols are the tris polyropylene glycolphosphates produced by interaction of phosphoric and propylene oxide as,for example, described in US Pat. Nos. 2,372,244 and 3,094,549.

DETAILED DESCRIPTION OF THE INVENTION The novelN-(piperazinylethyl)-carbamates (I) of this invention are obtained byreacting at an elevated temperature (a) an N-hydrocarbylcarbamate withtriethylenediamine or (b) an N-hydrocarbylcarbamate, triethylenediamineand an added alkylating agent.

In process (a), where the N-hydrocarbylcarbamate is reacted withtriethylenediamine, the process and products thereof can beillustratively represented as follows:

wherein R has the same meaning as hereinbefore defined.

Process (b) where the N-hydrocarbylcarbamate, triethylenediamine and anadded alkylating agent are reacted together can be illustrativelyrepresented as follows:

omom-N N-- m Rio o n wherein R has the same meaning as previouslydefined, R is selected from the group consisting of CH straight chainlower alkyl, CH O and straight chain lower alkoxy, R, is selected fromthe group consisting of CH and straight chain lower alkyl and with theproviso that when R is CH or straight chain lower alkyl then R is CH;and when R, is CH 0 or straight chain lower alkoxy, the alkyl groupthereof has the same number of carbon atoms as R In conducting process(a) or (b) of this invention, the N-hydrocarbylcarbamate employed as astarting material is preferably reacted with triethylenediamine in thepresence of an inert organic solvent. The inert organic solvent can beany organic solvent which is inert under the conditions of the reaction,e.g., does not enter into reaction with any of the reactants employed orin any way interfer with the progress of the reaction. Suitable inertorganic solvents include benzene, toluene, xylene, naphthalene, decalin,chlorobenzene, o-dichlorobenzene, bromobenzene, etc.

Advantageously, processes (a) and (b) are conducted at a temperatureranging from about C. to about 300C. and preferably at a temperaturewithin the range of about C. to about 200C. Approximately stoichiometricquantities of the reactants are generally employed in processes (a) and(b) although, if desired, an excess of the carbamate can be utilized.The progress of the conversion of the N-hydrocarbylcarbamate to thedesired piperazine derivative can be followed by any of the appropriateanalytical techniques such as infrared spectrographic analysis, etc. Thedesired N-(piperazinylethyl)-carbamate can be isolated from the reactionmixture of process (a) or (b) by conventional procedures in organicchemical operations such as by extraction, distillation, precipitationas the hydrochloric acid salt, etc.

The N-hydrocarbylcarbamates utilized as starting materials in process(a) and (b) are for the most part known compounds which can be preparedby methods conventional in the art for the preparation of N-substitutedcarbamates. A particularly convenient method involves the reaction ofthe appropriate chloroformate and appropriate hydrocarbylamine; see, forexample, H. von Pechmann, Ber, 28, 855 (1895) for a description of thepreparation of ethyl- N-methylcarbamate from methylamine and ethylchloroformate as representative of the conditions required in preparingthis series of compounds. Another method for the preparation ofN-substituted carbamates involves the reaction of the correspondingN-substituted carbamyl halide with the appropriate alcohol for example,using the procedure described by Gattermann, Annalen 244,30 (1888) forthe reaction of carbamyl chloride itself with alcohols.

N-substituted carbamates can also be obtained by the alkylation ofolefins with urethane (ethyl carbamate) as described by Mueller andMerten, Ber, 98, 1097 (1965) and by condensation of aldehydes with alkylcarbamates as described, for instance, by Bischoff, Ber, 7, 628(1874).

Various embodiments of this invention are illustrated in the followingexamples which are to be considered not limitative:

EXA MPLE l Methyl N-phenyl-N-methylpiperazinylethylcarbamatc A total of15.2 g. of methyl N-phenyl carbamate, 5.6 g. of triethylenediamine and10 ml. of methyl carbonate were added with mixing at room temperature to100 ml. of chlorobenzene. The mixture was heated over a period of aboutminutes to refluxing temperature and the refluxing operation wascontinued over a period of about 5 hours.

Following dilution of the reaction mixture with ether, it was extractedwith four portions of hydrochloric acid (5 percent by volume) andfinally with water. In the next step the resulting aqueous acid layerwas washed with two portions of ether. The organic layers were combined,washed with a saturated salt solution and finally dried over magnesiumsulfate and after evaporation of the ether, residue containing theunreacted starting carbamate weighing 10.2 grams was obtained.

The acid aqueous layer was made basic through the addition of sodiumhydroxide (10 percent by volume), saturated with sodium chloride andthen extracted with five portions of ether. After the ether phase hadbeen washed to neutrality with a saturated salt solution, it was driedover magnesium sulfate and on evaporation there was recovered 1 1.3 g.(82 percent of the theoretical yield) of the compound having theformula:

boiling point l56l58C. at 0.5 mm. Hg, which was identified by infraredspectrographic nuclear magnetic resonance analyses as well as byelemental analysis.

Analysis Calcd for C,,H,,0,N,= C,65.95; H,8.36; N,15.15. Found: C,65.l4;H,8.42; N,15.22.

EXAMPLE 11 Butyl N-phenyl-N-butylpiperazinylethylcarbamate To 35 ml. ofbutyl carbonate there was added with mixing at room temperature 38.74 g.of butyl N-phenylcarbamate, and 22.48 g. of triethylenediamine afterwhich the reaction mixture was heated with mixing for hours at 150C. Inthe next step, the resulting mixture was diluted with ether and thenworked up into basic and neutral fractions utilizing the generalprocedure employed in Example 1.

From the basic phase there was recovered a total of 19.68 g. (50.8percent of the theoretical yield) of the compound having the formula:

boiling point 185-187C. at 0.4 mm. Hg, which was identified by infraredspectrographic analysis as well as by elemental analysis.

Analysis-Calcd. for C H O N C,69.77; H,9.76; N,1 1.62. Found: C,69.39;H,9.70;N,l 1.81.

EXAMPLE m Butyl N-phenyl-N-methylpiperazinylethylcarbamate In thisexample 38.6 g. of butyl N-phenylcarbamate, 13.0 g. of methyl hexanoate,and 12.4 g. of triethylenediamine were heated with mixing at C. for 24hours. The reaction mixture was cooled, diluted with ether and water andthen filtered. The resulting etheral portion was washed with 1 Nhydrochloric acid until acidic while the combined aqueous phase waswashed with ether, made basic with sodium hydroxide (10 percent byvolume) and finally continuously extracted with ether. After the etheralphase had been dried over magnesium sulfate, there was obtained onevaporation of the ether approximately 10 g. of a basic mixture which ondistillation yielded 5.5 g. (16 percent of the theoretical yield) of thecompound of the formula:

The above product was identified by infrared spectrographic and nuclearmagnetic resonance analyses.

EXAMPLE IV (illaUllr-N N (Ill;

boiling point 18lC. at 0.7 mm. Hg. The compound was further identifiedby infrared, nuclear magnetic resonance and vapor phase chromatographyanalyses.

Analysis Calcd. for C I-1 N 0 :C,67.67;H,9.15; and N,l3.l6. Found:C,67.70; H,9.04; N,13.50.

EXAMPLE V Using the procedure of Example 1 but replacing methylN-phenylcarbamate with:

hexyl N-methylphenylcarbamate ethyl N-vinylcarbamate,

octyl N-pentenylcarbamate,

ethyl N-naphthylcarbamate,

butyl N-ethylxylylcarbamate,

propyl N-cyclohexylcarbamate,

methyl N-benzylcarbamate, or

N-naphthyl-N-m ethylpiperazinylethylcarba-N-ethylxylyl-N-methylpiperazinylethylcarba- EXAMPLE VI A total of 7.8 g.of methyl N-phenylcarbamate and 3.0 g. of triethylenediamine wererefluxed in 100 ml. of chlorobenzene for 6 hours. After the reactionmixture had been filtered, it was worked up into basic and neutralfractions using the general procedure of Example I. The basic fractiongave in excess of 50 percent of the theoretical yield of a product whichwas shown to be identical to the compound obtained in Example I (i.e.,methyl N-phenyl-N-methylpiperazinylethyl carbamate) by infraredspectrographic and vapor phase chromatographic analyses.

EXAMPLE VII Using the procedure of Example VI but replacing methylN-phenylcarbamate with phenoxyethyl N-phenylcarbamate there was obtainedin good yield phenoxyethylN-phenyl-N-phenoxyethylpiperazinylethylcarbamate.

EXAMPLE VIII Employing the procedure of Example I but substituting ethylcarbonate, n-propyl carbonate and hexyl carbonate for methyl carbonatethere are obtained in comparable yield:

methyl-N-phenyl-N-ethylpiperazinylethylcarbamate,

methyl-N-phenyl-N-n propylpiperazinylethylcarbamate, and

methyl-N-phenyl-N-hexylpiperazinylethylcarbamate, respectively.

Highly useful polyurethane foams can be prepared in which the novelN-(piperazinylethyl)-carbamates of this invention are employed ascatalysts. The preparation of a typical foam product is set forth in thefollowing preparation:

Using a mechanical blender, parts by weight of polyol of equivalentweight 133 which is a blend of (i) an adduct of propylene oxide and amethylene bridged polyphenyl polyamine mixture obtained by acidcondensation of aniline and formaldehyde and (ii) a glycerol-propyleneoxide adduct, 2 parts by weight of a water-soluble silicone-glycolcopolymer cell control agent and foam stabilizer, and 3.2 parts byweight methyl N-phenyl-N-methylpiperazinylethylcarbamate are mixedtogether after which 32 parts by weight of a blowing agent, which isstabilized trich lorofluoromethane, is added. To the resulting mixtureIS added, as rapidly as possible, l l2 parts by weight of polymethylenepolyphenyl isocyanate of equivalent weight 113 (PAPI). The mixturethus-obtained is stirred with a high speed stirrer for approximately 30seconds and then is poured into an open mold (7 X7 X12 inches). Theresulting foam, which is allowed to rise freely, is cured at roomtemperature (about 20 to 25C. for 7 days and afterwards subjected tophysical testing. A polyurethane foam suitable for a wide variety ofcommercial applications, such as in the preparation of packagingcontainers, structural panels, etc. is obtained.

What is claimed is:

l. A compound of the formula:

wherein R is a member of the group consisting of phenyl, tolyl, xylyland naphthyl; and R and R are selected from the group consisting ofstraight chain lower alkyl of not more than four carbons.

2. The compound of claim 1 wherein R is phenyl, R is CH and R is CH 3.The compound of claim 1 wherein R is phenyl and R and R each are CH(CI-l 4. The compound of claim 1 wherein R is phenyl, R is CH (CH and Ris CH UNITED STATES PATENT @FFICE CERTEFECATE @F CRRETIN Patent NO. D td March 6,

Invent-(5) Franklin W. Abbate and William J. Farrissey, Jro

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Title Page:

The References Cited should include:

3,131,213 4/64 Surrey 260/268R 2,914,528 11/59 Craig. 260/268R Signedand sealed this 10th day of July 1973.

(SEAL) Attesc:

EDWARD M.FLETCHER,JR. ne Tegtmeyer Attes'tlng Officer ActingCommissioner of Patents F ORM PO-IOSO (10-69) USCOMM-DC 60376-969 w u.s.GOVERNMENT am-mm: OFFICE: I969 0-356-330

1. A compound of the formula: wherein R is a member of the group consisting of phenyl, tolyl, xylyl and naphthyl; and R1 and R2 are selected from the group consisting of straight chain lower alkyl of not more than four carbons.
 2. The compound of claim 1 wherein R is phenyl, R1 is CH3 and R2 is CH3.
 3. The compound of claim 1 wherein R is phenyl and R1 and R2 each are CH3(CH2)3. 